fix analyzer issue

Author: sensuikan1973

lib/home/setting_dialogs/bestpath_count_availability_setting_dialog.dart

@@ -31,7 +31,7 @@ class BestpathCountSettingDialog extends StatelessWidget {
         if (snapshot.hasData) _enabled.value = snapshot.data;
         return ValueListenableBuilder<bool?>(
           valueListenable: _enabled,
-          builder: (final _, final value, final __) {
+          builder: (final _, final value, final _) {
             if (value == null) return const CupertinoActivityIndicator();
             return Column(
               mainAxisSize: MainAxisSize.min,

lib/home/setting_dialogs/book_file_path_setting_dialog.dart

@@ -40,7 +40,7 @@ class _BookFilePathSettingDialogState extends State<BookFilePathSettingDialog> {
             const Padding(padding: EdgeInsets.symmetric(horizontal: 10)),
             ValueListenableBuilder<String?>(
               valueListenable: _selectedFilePath,
-              builder: (final _, final value, final __) {
+              builder: (final _, final value, final _) {
                 if (value == null) return const Text(' ');
                 return Expanded(child: SelectableText(value));
               },

lib/home/setting_dialogs/hint_step_by_step_setting_dialog.dart

@@ -21,7 +21,7 @@ class HintStepByStepSettingDialog extends StatelessWidget {
         if (snapshot.hasData) _enabled.value = snapshot.data;
         return ValueListenableBuilder<bool?>(
           valueListenable: _enabled,
-          builder: (final _, final value, final __) {
+          builder: (final _, final value, final _) {
             if (value == null) return const CupertinoActivityIndicator();
             return Column(
               mainAxisSize: MainAxisSize.min,